The present invention relates to an information filtering apparatus and a method therefor, more particularly to a information filtering apparatus which filters information for interests and tastes of users chosen among a plurality of the information and selects services for interests and tastes among services and recommends the services to the users.
The information filtering apparatus selects and filters the information meeting the interests and the tastes of the users among the plurality of the information. Moreover, in a broader sense, the information filtering apparatus selects the services which meet the interests and tastes of the users among the plurality of the services and recommends them to the users. Filtering of the information, described later, shall include the recommendation of the services.
A conventional information filtering apparatus has adopted a method for directly retrieving primary information which is an object of the interest itself. The conventional information filtering method also has adopted a method for fetching out the desired information by filtering secondary information (e.g., a title, a name of author, a keyword, and a word appearance frequency).
In recent years, a filtering technology referred to as "a social filtering" and "a collaborative filtering" has been studied, in which evaluation results (evaluation values) of the users for objective items is previously stored as item evaluation information, and the evaluation value evaluated in the past by the user who demanded the filtering (hereinafter referred to as a "demander") is compared with the evaluation value evaluated in the past by a user other than the demander. In this conventional filtering technology, a user having a taste similar to that of the demander is then found out and an item highly evaluated by this user, which is not found out yet, is chosen. In this conventional filtering technology, relating to the evaluation values evaluated for individual items by the user and the evaluation values evaluated by other users, the relation between the demander and other users is studied by means of the evaluation values of the demander and other users, whereby the evaluation value of the demander is estimated as to the item which is not evaluated by the demander but by other users. The evaluation value estimated in such a manner is called "suitability".
However, in the conventional information filtering apparatus as described above, when the user shows an unbalanced trend for the specified interest and the taste, there has been a problem that the unbalanced trend has an effect on the suitability.
Moreover, in the conventional information filtering apparatus, many pieces of item evaluation information are a required to estimate the evaluation value with a high accuracy. A new objective item, in general, has a small number of the item evaluation information, so that there has been a problem that the estimation accuracy of the evaluation value gets worse as the objective item is newer.